systemd/man/systemd-ask-password.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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<refentry id="systemd-ask-password"
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-ask-password</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Lennart</firstname>
        <surname>Poettering</surname>
        <email>lennart@poettering.net</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-ask-password</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-ask-password</refname>
    <refpurpose>Query the user for a system password</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>systemd-ask-password <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt">MESSAGE</arg></command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-ask-password</command> may be used to query
    a system password or passphrase from the user, using a question
    message specified on the command line. When run from a TTY it will
    query a password on the TTY and print it to standard output. When
    run with no TTY or with <option>--no-tty</option> it will query
    the password system-wide and allow active users to respond via
    several agents. The latter is only available to privileged
    processes.</para>

    <para>The purpose of this tool is to query system-wide passwords
    -- that is passwords not attached to a specific user account.
    Examples include: unlocking encrypted hard disks when they are
    plugged in or at boot, entering an SSL certificate passphrase for
    web and VPN servers.</para>

    <para>Existing agents are: a boot-time password agent asking the
    user for passwords using Plymouth; a boot-time password agent
    querying the user directly on the console; an agent requesting
    password input via a
    <citerefentry project='man-pages'><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    message; an agent suitable for running in a GNOME session; a
    command line agent which can be started temporarily to process
    queued password requests; a TTY agent that is temporarily spawned
    during
    <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    invocations.</para>

    <para>Additional password agents may be implemented according to
    the <ulink
    url="http://www.freedesktop.org/wiki/Software/systemd/PasswordAgents">systemd
    Password Agent Specification</ulink>.</para>

    <para>If a password is queried on a TTY, the user may press TAB to
    hide the asterisks normally shown for each character typed.
    Pressing Backspace as first key achieves the same effect.</para>

  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>--icon=</option></term>

        <listitem><para>Specify an icon name alongside the password
        query, which may be used in all agents supporting graphical
        display. The icon name should follow the <ulink
        url="http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html">XDG
        Icon Naming Specification</ulink>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--timeout=</option></term>

        <listitem><para>Specify the query timeout in seconds. Defaults
        to 90s. A timeout of 0 waits indefinitely. </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--echo</option></term>

        <listitem><para>Echo the user input instead of masking it.
        This is useful when using
        <filename>systemd-ask-password</filename> to query for
        usernames. </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--no-tty</option></term>

        <listitem><para>Never ask for password on current TTY even if
        one is available. Always use agent system.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--accept-cached</option></term>

        <listitem><para>If passed, accept cached passwords, i.e.
        passwords previously typed in.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--multiple</option></term>

        <listitem><para>When used in conjunction with
        <option>--accept-cached</option> accept multiple passwords.
        This will output one password per line.</para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="help" />
    </variablelist>

  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure code
    otherwise.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>